Artificial turf has long been used in athletic venues. It is a general object of such surfaces to mimic natural grass turfs while eliminating the high maintenance required and poor durability of the same. However, much concern has arisen about the propensity for certain types of injury associated with the product. Indeed, grass surfaces provide excellent shock-absorbing properties and excellent traction for athletes as they traverse the turf, yet conventional synthetic turfs tend to fall short in these areas. Moreover, conventional synthetic turfs tend to be abrasive, rendering them inappropriate for such sports as soccer and lacrosse. In addition, unnatural ball action on conventional turfs inhibits play of these and other sports.
More recently, artificial turf filled with a mixture of sand and rubber has been shown to address many of these problems by reducing the potential for certain turf-induced injuries and by greatly reducing abrasion. For example, U.S. Pat. No. 4,337,283 discloses an artificial turf comprising a subsurface, a pile fabric having a flexible backing on the subsurface, and a compacted top-dressing layer comprising a mixture of from 25 to 95 volume percent resilient particles such as rubber, and from 5 to 75 volume percent fine sand. The top-dressing layer is interspersed among the pile elements of the pile fabric and on the backing. The purpose of the top-dressing layer is to stabilize the pile elements, prevent graininess (i.e., prevent the tendency of the pile fabric to lay in a given direction), absorb shock, and improve the footing of a player running or walking across the surface. Although the use of fine sand in the top-dressing layer adds weight and reduces sponginess to the pile fabric layer and is less abrasive than "large" sand, it still suffers from undesirable abrasiveness. In addition, the turf system relies on gravity and the slope of the sub-base for water drainage.